Schondorf, R, Benoit, J, Wein, T et al. · Journal of the autonomic nervous system · 1999 · DOI
This study looked at whether ME/CFS patients experience problems with blood pressure and heart rate when standing up quickly, a condition called orthostatic intolerance. Researchers tested 75 ME/CFS patients and 48 healthy controls using a tilt table test and other physical challenges. They found that 40% of ME/CFS patients had orthostatic intolerance compared to fewer healthy controls, suggesting this may be an important symptom in some patients that could be treated.
This study identifies orthostatic intolerance as a distinct, treatable physiological abnormality present in a significant subgroup of ME/CFS patients, which could explain why some patients experience dizziness and fatigue upon standing. Understanding that OI affects only some ME/CFS patients suggests the disease may involve multiple distinct biological subtypes, potentially requiring different treatment approaches. This work supports developing and testing orthostatic tolerance-targeted interventions for eligible patients.
This study does not prove that orthostatic intolerance causes ME/CFS or that correcting OI will cure the disease—it only shows an association in one direction. The cross-sectional design cannot establish whether OI develops as a consequence of CFS or exists independently. The study also does not prove that all ME/CFS patients would benefit from OI-specific treatments, since 60% of patients showed no laboratory evidence of OI.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Schondorf, R, Benoit, J, Wein, T, & Phaneuf, D (1999). Orthostatic intolerance in the chronic fatigue syndrome.. Journal of the autonomic nervous system. https://doi.org/10.1016/s0165-1838(98)00177-5
BibTeX
@article{mecfsatlas-schondorf-1999-orthostatic-intolerance,
author = {Schondorf, R and Benoit, J and Wein, T and Phaneuf, D},
title = {Orthostatic intolerance in the chronic fatigue syndrome.},
journal = {Journal of the autonomic nervous system},
year = {1999},
doi = {10.1016/s0165-1838(98)00177-5},
note = {PubMed: 10189122},
url = {https://www.mecfsatlas.com/evidence/schondorf-1999-orthostatic-intolerance},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/schondorf-1999-orthostatic-intolerance
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